Proteinuria and fusion of podocyte foot processes in rats after infusion of cytokine from patients with idiopathic minimal lesion nephrotic syndrome.

Abstract

BACKGROUND/AIMS:

We report on the isolation of a factor secreted by peripheral blood mononuclear cells from patients with idiopathic minimal lesion nephrotic syndrome (IMLNS) in relapse and its effect on proteinuria and podocyte morphology in the rat.

METHODS:

Peripheral blood mononuclear cells from patients with IMLNS (in relapse and in remission) and patients with focal segmental glomerulosclerosis were cultured for 72 h. Supernatants from 20 x 10(6) cultured cells were separated by liquid chromatography into three fractions according to markers (bovine serum albumin, beta-amylase, and apoferritin). Each supernatant fraction was infused into rats for 5 days using an osmotic pump. Proteinuria, 24-hour albumin excretion or albumin/creatinine ratio in a 24-hour urine collection, was measured daily starting 3 days prior to fraction infusion. Renal tissue was obtained for electron microscopy studies. The beta-amylase fraction underwent electrophoresis using isoelectric focusing gel.

RESULTS:

When protein excretion was compared prior to and during supernatant fraction infusion, a significant increase in proteinuria was observed only when beta-amylase fraction from IMLNS patients in relapse was infused (p < 0.05). Protein electrophoresis of the beta-amylase fraction showed a single band at pH 6.0 only in samples from IMLNS patients in relapse. The band was composed of two proteins, beta-amylase and a 100-kDa glycoprotein. Fusion of foot processes was observed only when the beta-amylase fraction from IMLNS patients in relapse was infused.

CONCLUSIONS:

The infusion of the beta-amylase fraction containing a 100-kDa glycoprotein from IMLNS patients in relapse induced proteinuria and effacement of foot processes in the rat. This protein may play a role in the pathogenesis of IMLNS.

• Authors: Eduardo H Garin, Paul F Laflam, Karl Muffly
• Journal: Nephron. Experimental nephrology (Nephron Exp Nephrol) Vol. 102 Issue 3-4 Pg. e105-12 ( 2006) ISSN: 1660-2129 [Electronic] Switzerland
• PMID: 16330882 (Publication Type: Journal Article)
• Copyright: 2006 S. Karger AG, Basel.

Chemical References

• Cytokines
• Glycoproteins
• Serum Albumin, Bovine
• Apoferritins
• beta-Amylase

Topics

• Adolescent
• Adult
• Animals
• Apoferritins (administration & dosage, blood)
• Blood Protein Electrophoresis
• Child
• Child, Preschool
• Cytokines (administration & dosage, blood)
• Electrophoresis
• Female
• Glomerulosclerosis, Focal Segmental (blood)
• Glycoproteins (blood, chemistry, pharmacology)
• Humans
• Hydrogen-Ion Concentration
• Infusion Pumps
• Kidney (pathology)
• Male
• Molecular Weight
• Nephrotic Syndrome (blood)
• Podocytes (pathology)
• Proteinuria (etiology)
• Rats
• Rats, Sprague-Dawley
• Recurrence
• Serum Albumin, Bovine (administration & dosage, pharmacology)
• beta-Amylase (administration & dosage, blood)